Tropical Storm Erika's future highly uncertain

By: Dr. Jeff Masters , 2:21 PM GMT on September 02, 2009

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The tropical wave we were calling Invest 94 finally decided to stop dawdling and become Tropical Storm Erika yesterday. However, Erika seems intent upon keeping us guessing about its intentions, as the storm's future track and intensity remain highly uncertain. After a modest burst of intensification to a 60 mph tropical storm last night, Erika has become quite disorganized this morning. The Hurricane Hunters found multiple swirling centers inside Erika early this morning, and the main center took a jump to the southwest to relocate itself under a batch of intense thunderstorms. The exact location and path of Erika remain uncertain at this point, and it is possible the storm will have another center relocation later today. Wind shear analyses from the University of Wisconsin diagnose a moderate 10 - 15 knots of shear over Erika, a decrease from yesterday. SSTs are warm, 29°C. Why, then, is Erika so disorganized? The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone. Upper air data from Guadeloupe and Saint Martin from last night show a complicated shear pattern in Erika's region, with 30 knot winds out of the south to southwest at 200 mb height, nearly calm winds between 300 - 500 mb, and northeasterly winds of 10 - 20 knots from the surface to 500 mb. Some extremely dry air with humidities near 10% was present in a thin layer near 600 mb on the Guadeloupe sounding, so dry air from the Saharan Air Layer is probably being injected by a northeasterly jet of wind into the core of Erika. The shear of 30 knots at the top of the storm is ripping away the heat and moisture Erika's thunderstorms are lifting there, and the result of the shear and dry air is a very disorganized tropical storm.

Erika is embedded in a weak steering current pattern, and the future track of the storm will depend greatly upon how strong the storm gets over the next few days. A stronger Erika will extend higher into the atmosphere and be steered more to the northwest by upper-level winds. A weaker Erika will be steered more by the low-level winds, which will keep the storm on a more westerly track. Given the complicated nature of the wind shear pattern in the region, it is difficult to forecast how strong Erika will get. Virtually anything can happen over the next five days, from dissipation (as forecast by the ECMWF model) to intensification to a Category 3 hurricane (as forecast by the HWRF model). Large-scale wind shear is expected to increase to 20 - 25 knots between 3 - 4 days from now, so Erika will have to deal with an increasing amount of adversity. The storm is a long-term threat to the Bahamas and U.S. East Coast, particularly if the storm stays weak over the next three days. Potential landfall solutions from the models range from Florida on Tuesday (GFS model) to North Carolina on Wednesday (Canadian model).


Figure 1. Morning image of Tropical Storm Erika, showing a false center over Guadaloupe--one of several surface swirls the Hurricane Hunters found in the storm.

Elsewhere in the tropics
The tropical wave off the coast of Africa we were watching on NHC's Tropical Weather Outlook as having a low chance of developing into a tropical depression has been done in by the dry air of the Sahara, and is no longer a threat to develop. A large and well-organized tropical wave will emerge from the coast of Africa on Thursday, and several of the models develop this low into a tropical depression by early next week. The remains of an old cold front off the coast of North Carolina could serve as a breeding ground for some tropical development Friday or Saturday, but anything that forms in this region would get swept quickly northeastward into New England by Sunday without enough time to become a tropical depression.

Hurricane Jimena nears Baja
Hurricane Jimena has steadily weakened over the past day, and is now down to a Category 2 hurricane with 105 mph winds. The storm should continue to steadily weaken over the next 24 hours as the waters under the hurricane cool from 28°C to 27°C. Jimena is battering a relatively unpopulated stretch of coast, and largely spared the tourist mecca on the southern tip of Baja. It now appears unlikely that moisture from Jimena will reach the Southwestern U.S., and the hurricane appears poised to stall out over Baja and die five days from now.


Figure 2. Hurricane Jimena on Tuesday, Sep. 1, 2009, as seen by NASA's MODIS instrument. Image credit: NASA Earth Observatory.

Baja's hurricane history
The most powerful hurricane on record to hit the west coast of Baja occurred last year, when Hurricane Norbert made landfall on the central Baja coast with sustained winds of 105 mph (Category 2) . Norbert's central pressure of 956 mb at landfall made it the 3rd strongest hurricane to hit the Pacific coast of Mexico since record keeping began in 1949. Norbert killed eight, knocked out power to 20,000 homes, and damaged or destroyed 40% of the homes on the islands of Margarita and Magdalena. Norbert crossed the Baja Peninsula and made landfall on Mainland Mexico as a Category 1 hurricane with 85 mph winds.

Only two major hurricanes have made landfall on Baja since record keeping began in 1949. Both hurricanes hit the east (Gulf of California) side of Baja. The first was Hurricane Olivia of 1967. Olivia made landfall on October 13, 1967 as a Category 3 hurricane with 125 mph winds. Due to its small size and the unpopulated region of coast it hit, damage was minimal. The second major hurricane was Hurricane Kiko, which made landfall on August 27, 1989, as a Category 3 hurricane with winds of 115 mph (minimal Category 3). Kiko was a small hurricane and hit a relatively unpopulated area, resulting in no loss of life and only scattered reports of damage.


Figure 3. A plot of all the major hurricanes to pass within 200 miles of Mexico's Baja Peninsula since 1949. Image credit: NOAA Coastal Services Center.

California fire webcams
As I discussed in yesterday morning's post, you can use our wundermap for Los Angeles with the fire layer turned on to see where the fire and smoke are located, and track the temperatures and winds during today's air pollution event. We also have two webcams with views of the fire: Altadena and Tujunga.

I'll have an update by 4pm this afternoon, when the data from the next hurricane hunter flight into Erika will be available.

Jeff Masters

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Quoting OracleDeAtlantis:


I agree, but it's also evident that these multiple COC's are going to combine eventually to form a much larger circulation. This is how truly great systems are born. They start out coughing and choking under water, and when they finally get to the surface, they take this enormous breath that begins a perilous march westward.


The Oracle of Atlantis, huh? As in, a prophet of doom and destruction?

It's true that some powerful storms begin with broad and disorganized convection, and that as they consolidate multiple low level centers they grow into monsters. Sure. It's also true that many broad and disorganized areas of convection dissipate without ever amounting to much, because they're unable to consolidate. And that some which do consolidate, but face high sheer, never achieve anything close to their potential.

For now, the salient fact is that Erika is disorganized. Until she pulls it together, she's as much a potential thunderstorm as she is a potential major hurricane. There's no point focusing on one prospect at the expense of the other. Uncertainty is the watchword of the hour - sometimes, you just gotta keep hitting refresh, and waiting for more information.
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Quoting Patrap:


Mr. Ruger who travels with Patrap has 15 Solutions for any event in the Park or Uptown,..

Nice answer!!
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Quoting btwntx08:
shear tendency map here's a link
Link


"The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone."

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Well Erika might just dissipate if it moves away from the anticyclone; however, it could latch on to the anticyclone and strengthen. Thsi is a really complicated forecast. Even if Erika strengthens, as the ridge of high pressure builds in the Northeast USA, don't expect a recurvature. Erika has slowed down last night and even stalled a few times, this causing the weakness to weaken even more. However the NOGAPS and EURO show a recurvature but not till that ridge moves east at a fast clip. Possible because both these models have been more accurate then others with Bill and Danny. The NHC has Erika as a depression but there confidence on the intensity and track is very low and anything can change. The anticyclone is pretty much the only hope. Honestly we don't know what Erika will do, things need to come together for different scenarios to happen. The Southeast to Northeast US needs to watch this storm as well as Canada. It's a safe bet to say Bermuda will be safe.
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Quoting rwdobson:


From Dr M "The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone."

Why are you bothering with shear tools that have been shown to be worthless with Erika?



I am no expert, by all means. However it seems to me that in the case of Erika all tools, graphs, maps, and models have been useless. I have seen better predictions on this blog than I have from any other source. I believe she is one to still be watched. Just my opinion.

Quoting IKE:


Yeah, I see one....acting like a 12 year-old on here.


which one?
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Jeesum..Im sitting here typing away and the NOAA Radio Goes off with that creepy Weds Test and I nearly Jumped out me chair ans Broke a Hip..
Member Since: July 3, 2005 Posts: 426 Comments: 128685
NHC has a new plan.
If you see a cow in the air.......evacuate.
Seems a good plan to me now that Erica is about to enter the Carribbean.
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402. IKE
Quoting DestinJeff:


thanks Ike, but still no dice. i'll look some more, til i figure it out "HIDE" will have to suffice.

by the way, i swore i'd never ignore ... but i'm sure you know who is marked.


Yeah, I see one....acting like a 12 year-old on here.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting kmanhurricaneman:
stormpetrol, run a RGB loop and tell me what you think,lets compare

Erika catchin up to the old LLC moving slightly south of due west at a liitle faster clip, new center just about fully formed and becoming the dominant one at 16N/60W, taking a comma like shape, getting in gear one might say just my opinion, I guess I'll get blasted as usual :)
Member Since: April 29, 2007 Posts: 0 Comments: 7932
Quoting Dakster:


Who's convection?


Convection is a lucky guy.
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Anything happening with all those waves dr Masters numbered in his blog yesterday coming off Africa?
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Quoting btwntx08:
i just look at shear map right now the anticyclone is right over the center of erika and the the east side of the system is in 10-15 kts of shear and the worst shear right now is just south of pr


From Dr M "The trouble with the various wind shear analyses we use is that they take a crude average of winds over a thick layer to arrive at an average shear, and this large-scale average shear does not capture thin layers of shear that can dramatically affect a tropical cyclone."

Why are you bothering with shear tools that have been shown to be worthless with Erika?
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Quoting 1900hurricane:
Erika still has quite a long way to go structurally.



I agree, but it's also evident that these multiple COC's are going to combine eventually to form a much larger circulation. This is how truly great systems are born. They start out coughing and choking under water, and when they finally get to the surface, they take this enormous breath that begins a perilous march westward.

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Quoting stormpetrol:

You might be right, I maybe wrong or vice versa time will tell, so far I been pretty right regarding Erika, you have a right to your opinion , I have a right to mine, though I will not criticize you or anyone else for that matter, its just not my style, time will tell.

Very well said.
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this use to be a blogg discussing weather now it's an all out anything goes blog,hell if i wanted to discuss the news or personal stuff i 'll go on facebook or some other blogg ,lets get back to the reason this blogg was crear=ted for guys,THANKS!!!
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Quoting keys33070:
I have a really stupid stupid question, but the

I have a really stupid question, but this made me think about it. I am in Tavernier ( Mid Upper Keys), it seem that on most days during the rainy season the Keys get afternoon showers. However 95% of the time they split around us. Meaning Key Largo, and Islamorada get rain, but we stay dry. It drives me crazy --- I would love to see a nice storm roll through.


Yeah, it's weird how that happens. Luck of the draw I guess? We get the thunderstorms and rain in the afternoons a lot while my mother-in-law approx 15 miles away in another county never seems to..
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prove it
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WV Image

Member Since: July 3, 2005 Posts: 426 Comments: 128685
Quoting VoodooRue:


But has she discovered the alligator loose in the park yet?



Mr. Ruger who travels with Patrap has 15 Solutions for any event in the Park or Uptown,..
Member Since: July 3, 2005 Posts: 426 Comments: 128685
Quoting antonio28:
Erika will survive as a minimal TS or 50MPH for the next few days as she travel the NE caribbean nothing serious at this moment in term of winds for PR and the islands. =P :) Erikita we are waiting for you tiny little storm. LOL
but remember, rain is the big killer on the islands, not wind.
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Quoting Patrap:
NOLA Roux about a Month ago,she doubled in Size since this pic

she is so cute!
Member Since: September 5, 2007 Posts: 0 Comments: 3488
Quoting Patrap:
Exposed, tilted and diffuse..

Not a good way to Build a TC



But a good way to go west.
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381. IKE
DestinJeff...you then scroll down and click to add the person.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Breeze coming over Dominica from the south west as all moisture-laden clouds follow the same path being sucked into Erika's lower level just over 100 miles away in the Atlantic, approaching the islands very slowly.
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Exposed, tilted and diffuse..

Not a good way to Build a TC

Member Since: July 3, 2005 Posts: 426 Comments: 128685
Quoting Patrap:


Nola Roux is a Machine already,.I took her to Audubon Park yesterday,..and she discovered Squirrels,..and Joggers.

Squirrels made out fine,..Joggers?,well,that may rate a Blog Entry.
With her Ears Now fully Up,,she looks Like a Minature full Grown Sheperd

LOL


But has she discovered the alligator loose in the park yet?

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377. IKE
Quoting DestinJeff:
anybody having trouble with ignore feature ... have a couple i want to add, but just takes me to my own blog


That's what it's suppose to do. A list will then come up with the name added.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
stormpetrol, run a RGB loop and tell me what you think,lets compare
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Weak low pressure system starting to take shape along the stalled front across the GOM and N/C FL @ the NE GOM or about S of TLH.
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Quoting holynova:
What breed?


Oh Pat your dog is adorable. I miss having puppies around....LOL My two dogs are all grown
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Quoting justalurker:


how 24hr makes a difference here, just yesterday everyone had this going to category 1 heading anywhere from africa to US, now just a thunderstorm, to early to tell right now, iwould wait couple more advisories before dumping erika.

just like your old girlfriend when you breakup with here, next day your making a b**ty call.

and i'm not CASTING ANYTHING..


I think you bootycasted? ;)
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I have a really stupid stupid question, but the
Quoting TreasureCoastFl:


well, that sort of happens every afternoon anyway.. lol


I have a really stupid question, but this made me think about it. I am in Tavernier ( Mid Upper Keys), it seem that on most days during the rainy season the Keys get afternoon showers. However 95% of the time they split around us. Meaning Key Largo, and Islamorada get rain, but we stay dry. It drives me crazy --- I would love to see a nice storm roll through.
don't know where it is really coming from
Member Since: December 9, 2008 Posts: 0 Comments: 2498
disagree
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Quoting OSUWXGUY:


I'm with you 100%. I was surprised at how bearish the NHC was in its discussion and forecast intensity at 11AM.

Seems to me, we should still be in the wait and watch mode. The shear in the 200-300mb level doesn't seem to have a long lived cause (at least short term). The real westerlies won't be impacting Erika until between 60 and 72 hours according to SHIPS.

This still gives it the opportunity to become better organized. Whether it will or won't is pretty much a coin flip...

SHIPS Guidance Erika 12UTC


I notice that the shear forecast is still there at greater than 50 hours out, except the speed has dropped some (from the mid 20 kt) to staying in the teens compared from yesterday's output I saw.

Playing the ole waiting game until then.

DellOP
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Quoting stormpetrol:

You might be right, I maybe wrong or vice versa time will tell, so far I been pretty right regarding Erika, you have a right to your opinion , I have a right to mine, though I will not criticize you or anyone else for that matter, its just not my style, time will tell.

What is your opinion as to how or why she will not be effected by all that shear?
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with all Erika has against it it continues to hang on, if things got favorable she would be a beast. very determined system.. NHC leans toward dissapation it seems, down the road
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Quoting homelesswanderer:


Lol. No problem. I think I got it. part of the cold front is going to break off and turn N-S and drift bk over the NW gulf. Probably as a warm front. Bringing rain and that good ole icky, sticky, running down the side of your house, gulf moisture back. Lol. It just can't stand these low dew points. :)


haha sounds right
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Quoting tornadodude:


not sure lol


Lol. No problem. I think I got it. part of the cold front is going to break off and turn N-S and drift bk over the NW gulf. Probably as a warm front. Bringing rain and that good ole icky, sticky, running down the side of your house, gulf moisture back. Lol. It just can't stand these low dew points. :)
Member Since: August 15, 2008 Posts: 10 Comments: 3665
Quoting TheCaneWhisperer:


A weak storm comes west north west. Anything can happen. Look at Katrina.


how 24hr makes a difference here, just yesterday everyone had this going to category 1 heading anywhere from africa to US, now just a thunderstorm, to early to tell right now, iwould wait couple more advisories before dumping erika.

just like your old girlfriend when you breakup with here, next day your making a b**ty call.

and i'm not CASTING ANYTHING..
Member Since: August 18, 2009 Posts: 0 Comments: 157

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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